The credits (accompanied by organ music endemic to silent films), segue into title card: "A city street-----where laughter and tragedy rub elbows." A crowded block lined with tenement buildings, on Manhattan's Lower East Side, comes into view, followed by a look into the hallway of one of those buildings, then a shot is heard, a door to one of the apartments opens and a man holding a gun (Paul Muni) backs out, closes the door, puts the gun in his pocket, then walks down flights of stairs and into the busy street. While he passes along sidewalks teeming with human activity, an Irish American policeman berates a driver for parking in front of a hydrant, but when the driver removes his scarf, revealing a clerical collar, the abashed officer apologizes and offers to accompany the priest to the beat of "that cop on the next corner, he's not one of us". At that point, the shooter approaches and makes a gesture to speak, but the priest has already started to drive off, with the officer standing on the car's running board. Continuing to walk, the shooter reaches a police precinct and goes inside. Approaching the desk lieutenant (Clifford Dempsey), who asks, "Well, what's on your mind?", he replies, "I killed a man", explaining that the victim lived at 191 East 8th Street, was named John Harris, and "deserved to die". Asked for his own name, he hesitates and, spotting a wall calendar (showing May 1928) with a large ad for "Dyke & Co., Inc.", says "Dyke... James Dyke". To "Why are you giving yourself up?", he answers "It was the only thing to do".

The subsequent title card states: "Civilization demands its toll." In court, the killer is only willing to explain that "I never struck anybody in anger in all my life, but when I knew what he had done, I had to kill him." The judge (Henry Kolker) ultimately proclaims that "it is the duty of this court to sentence you to be executed at the state's prison during the week of August seventeenth."

Another title card: "Meanwhile------in a far-away home...." In the backyard of a countryside house, a young woman (Marguerite Churchill) is attending to her dogs, while her wheelchair-bound mother (Edith Yorke) is sitting nearby. A young man (John Mack Brown) arrives and greets the mother as "Mrs. Douglas", while she addresses him as "Robert" and tells him that it was on such a nice day as this that she last saw her son Joe. Robert hands her "your Columbus paper" and goes to greet the young woman, "Mary", who calls him "Bob". He unsuccessfully attempts to help Mary bathe one of the dogs and, when she falls trying to catch the dog, Bob impulsively kisses her and then proposes. Mary's mother calls and shows them a photograph of "James Dyke" in the paper with the lead "Condemned Man's Story Of His Life As It Should Have Been. A Lesson To Youth On Folly Of Crime By The Man Of Mystery". She tells them that he looks like the long lost Joe, but Mary says that it must be a mistake and there's happy news in that Bob proposed and after the marriage they will all live together.

Seeing the condemned man's photo, his mother insists on traveling to see him[edit]

The next title card describes "Gray walls, claiming their forfeits of liberty------and life." Prisoners are seen laboring in a field outside the prison and, as they return to the mess hall for a meal, a stage above the dining area features an orchestra consisting of African American prisoners, replete with a smiling bandleader, playing dance music for the prisoners as they eat. "Dyke" is brought to the office of the warden (DeWitt Jennings) who asks him about any family members whom he might like to contact, but the condemned man replies that he has no one. Leaving the office, he hears the jaunty melodies resonating from the dining area and says, "I didn't know you had music... here". A newspaper's printing machines are seen churning out the evening edition with the headings: "Mystery of Dyke's Identity Secret as Hour of Death Nears. Prisoner Staunchly Refuses to Divulge Secret of Himself or the Motive for His Crime Though He Faces Chair. James Dyke Maintains Silence as He Writes News Paper Articles Warning Youth on the Folly of Crime." One of the printers (unbilled Robert Homans) tells the other that he heard the paper was paying Dyke $2,500 for his writings and that Dyke was buying Liberty Bonds with the money.

Sitting in her bedroom, the infirm Mrs. Douglas visualizes long-ago memories of teenage Joe (unbilled Barton Hepburn) describing to his little sister Mary about being cast in a local Shakespeare play and that, at bedtime, instead of "goodnight", she should recite to him the "parting is such sweet sorrow" lines and he would respond with the "sleep dwell upon thine eyes" lines. Meanwhile, in the living room, Mary and Bob are in the midst of a party to celebrate their engagement and, as the happy couple and invited guests dance, everyone joins in singing a fast chorus of "Hosanna, hosanna, sing hosanna today". Briefly leaving their guests to check on Mrs. Douglas, Mary and Bob hear from her that despite fragile health, she has decided to make the long trip to visit "James Dyke" in prison, because the possibility that he might be Joe is making the uncertainty unbearable. Mary offers to travel on her mother's behalf, with Bob accompanying her on the trip and, as they are riding on the train, a little girl passenger who says that her name is Suzanne (unbilled Helen Parrish) asks if they also have a little girl, prompting Mary to tell Bob that she couldn't marry him "if this man in prison should be my brother", because "it wouldn't be fair to you" and "people are cruel".

Section of the plot which corresponds to the one-act play on which the film is based[edit]

A title card indicates "The test of the valiant." Dyke is escorted to the warden who commends his exemplary behavior and asks what he wants done with the $2,500 in Liberty Bonds which are being held here in the office for him. Dyke replies that he'll think of something. Also present is the chaplain (Richard Carlyle) who, along with the warden, tries to convince him to see the young lady who traveled a thousand miles to speak with him in the hope that he might be her long-lost brother. Dyke eventually agrees, but requests privacy for the meeting, which is granted. The warden initially speaks with Mary alone, learning that she is from the (fictitious) town of Pennington in Ohio, that her father died when she was a baby, that Joe, who is ten years older, left home fifteen years ago because "he wanted to be in the city" and has not been heard from since. She is certain, however, that she could recognize him from his reactions to their long-ago "goodnight" verses from Romeo and Juliet.

As Dyke is brought into the office, the warden, the chaplain and the guard exit, leaving the two alone, but with all doors open. After Mary's explanation, Dyke denies being her brother, says he is from Canada, not Ohio, and does not react to the verses. As Mary is about to leave, however, he asks her to repeat her name and her brother's name and then tells her that when he served with the Canadian Forces during the War (World War I), a fellow showed great valor in sacrificing his life and the dead hero's name was Joseph Anthony Douglas. There will be a record of his service, but as occasionally happens in war, other details, including his ultimate fate, may be lost. However, she should take the unopened envelope (containing the Liberty Bonds) to her mother and buy for her a Gold Star to put on the front door in honor of her fallen son. Mary asks if there is anything she can do and he responds that her touch would mean the world to him.

After hugging him, Mary leaves with the envelope and then "James Dyke" softly recites to himself the "sleep dwell upon thine eyes" lines as the time for his execution arrives. Back in Pennington, Mary and Bob sit by the piano, while Mrs. Douglas rests in her wheelchair on the porch, visualizing marching doughboys and then her young son's smiling face while he is also wearing such a uniform. As Bob and Mary wheel her inside, the front door slowly swings closed, revealing the display of a large star.

Screenwriters John Hunter Booth and Tom Barry adapted the one-act play by Holworthy Hall [on-screen credits indicate the name as Halworthy Hall] and Robert Middlemass, which twice closed on its respective Broadway opening nights: at the Nora Bayes Theatre on May 4, 1926 (with William L. Hildeburn in the leading role)[4] and a revival (with John H. Brown) at the Frolic Theatre on May 8, 1928.[5] The play, which has two lead and two supporting characters as well as one or two (depending on the staging) minor (jail attendant) characters, is described as taking place at "the Warden's office in the State's Prison at Wethersfield, Connecticut". Half an hour before the execution, the chaplain and the warden are making a final attempt at persuading "James Dyke" to reveal his identity. He is allowed to meet and converse with a young woman named Josephine Paris who believes that he might be her long lost brother. Following her departure, the condemned man, the chaplain and the warden exit the stage.[6]

A fleeting character in the film, played by minor, unbilled, actor Henry Hall,[7] is referenced as "Harold Everett Porter", the birth name of the play's co-author, whose pen name was a nod to Holworthy Hall, the dormitory at his alma mater, Harvard University.

Filmed concurrently with The Valiant, its Spanish-language version, El valiente, directed for Fox by Richard Harlan, was screened in those foreign and domestic venues which requested such specific non-English-language versions of Hollywood product, and ultimately had its New York premiere in November 1930, 18 months after the original film completed its run. The protagonist was portrayed by Juan Torena, the role played by Marguerite Churchill went to Angelita Benítez, while John Mack Brown's part was taken by Guillermo del Rincón. Carlos Villarías who, the following year, would play Bela Lugosi's iconic role as Dracula in that production's concurrently filmed Spanish-language version, was cast in Henry Kolker's part as the judge.[8]

Ten tears later, Fox revived the property as The Man Who Wouldn't Talk, a B-picture directed by David Burton, with stars Lloyd Nolan, Jean Rogers and Richard Clarke. Released in January 1940, the film followed Hall's and Middlemass' basic plot outline, but used a different screenplay, reworked by a number of writers, and appended an extended World War I flashback, resolving it all with a happy ending.

There were also two additional adaptations during early days of the period referenced as the Golden Age of Television. On November 29, 1948, NBC's half-hour anthology drama program Chevrolet on Broadway presented Paul Muni in a live, abbreviated recreation of his film performance from nearly twenty years earlier and, on October 23, 1950, CBS' half-hour anthology drama Lux Video Theatre broadcast another abbreviated version, with Zachary Scott as the man claiming to be "James Dyke" and Wendy Drew as "The Girl".

Shortly after The Valiant's premiere on May 19, 1929, Fox cast the two leads, Paul Muni and Marguerite Churchill, in their next feature, Seven Faces, directed by Berthold Viertel, which was released less than seven months later, on December 1. Between 1929 and 1932, Marguerite Churchill appeared in a total of fourteen features, while Paul Muni acted in only four, with the remaining two being Scarface and I Am a Fugitive from a Chain Gang.

In 1994, film historian Jim Knusch, the host and writer of Manhattan Neighborhood Network's long-running public-access TV show Professor Kinema, interviewed William K. Everson, who had presented school-auditorium screenings of his 16mm preservation print of The Valiant in 1973 and 1977,[9][10] and whose admiration of William K. Howard's directorial skill led him to rearrange the order of his given names, Keith William, so as to reflect the form "William K."[11] In the course of the hour-long interview, Everson, who died less than two years later, recounted a lifetime devoted to film preservation and mentioned that during a 1950s stint as a member of the 20th Century Fox publicity department, he requested permission to make the preservation copy and, within a decade, when the studio's own 35mm film material had deteriorated, his copy of The Valiant turned out to be the only one known to exist.